Hi!How old are they? Are they currently molting?
Pearls can be sexed once they've molted into their adult feathers. Boys will lose their pearl pattern, but girls will keep them. It's a bit more complicated with pearl pieds, as the males take longer to lose pearling and tail barring.
The image isn't loading big for me, and I'm no expert, but this bird may be molting out of their pearls if I'm seeing it right. This would indicate male.